The present invention relates to a new and improved construction of apparatus for stacking printed products arriving in an imbricated product formation or stream, such as newspapers, periodicals and the like. The invention further concerns apparatus for destacking a stack which has been formed with the aid of the aforementioned stacking apparatus or stacker.
Generally speaking, the stacking apparatus of the present development is of the type comprising a rotatably driven winding mandril for winding-up the imbricated product formation and a separation layer operatively associated or connected with the winding mandril.
In German Patent No. 1,244,656, published July 13, 1967, there is disclosed an apparatus for storing veneer sheets, wherein the veneer sheets reposing upon a pressure band are fed from below to a drum. The revolvingly driven pressure band extends almost along the entire circumference of the drum, and therefore, serves both for the infeed and also for the support of the loose veneer sheets before and during the winding operation. The individual wound layers or package plies are separated from one another by a separation or partition band connected with the drum. This separation band is placed over the veneer sheets at the region of a winding gap and is wound-up along with the veneer sheets. Since the outermost ply or layer of the thus formed package must be supported by the pressure band, the package cannot be readily removed from the stacking apparatus. As a rule, the package remains in the stacker apparatus until such time as it is destacked, this stacker apparatus being convertible into the destacking apparatus by carrying out appropriate equipment conversion manipulations, so that the destacking apparatus cannot be employed during the storage time of the stack for the formation of a new stack.
Also, in German Patent No. 2,207,556 published August 30, 1973, there is disclosed a stacker apparatus of the previously mentioned type, wherein the printed products arriving in an imbricated product formation are brought together by means of winder or winding bands both at the top surface and also at the bottom surface thereof. The imbricated product formation is retained between the winding bands. These winding bands together with the intermediately reposing printed products are infed from above, i.e. overhead, to the winder drum and wound thereon. After the winder drum has been filled, then the ends of both winding bands are firmly lashed together in order to retain the finished package. The need to provide two winding bands is associated with a corresponding complication in the equipment design and the expenditure in materials. Additionally, notwithstanding the presence of two winding bands, in many instances it is necessary to provide side or cheek plates at the winder drum, in order to prevent any disintegration of the stack or a positional change of the printed products within the imbricated product formation during manipulation of the finished stack.